Threaded closure for pressurized containers

Abstract

A threaded closure for pressurized containers, typically for carbonated beverages is disclosed. The closure includes a deformable liner of non-vinyl polymer which is cold formed in the closure using known techniques in such manner that the liner physically bonds to the inner surface of the end wall of the closure to be retained thereby in the absence of a peripheral lip or projections on the inner surface of the end wall of the closure. The closure itself may be either injection molded or compression molded. The usual tamper indicating ring is formed to include frangible bridge members either by molding or a separate slitting operation. The pivotally mounted tabs for separating the tamper-indicating ring are sufficiently rigid to avoid flexing at points other than at an outer edge hinge axis where pivoting is possible only to a limited degree, thus assuring the severing of the frangible bridge members at an early stage of opening of the closure.

I claim:  
     
       1. In a threaded closure for sealing a container having a corresponding threaded finish, said closure having a tamper-evident ring frangibly interconnected to said closure at a circular free edge thereof, said container defining an annular recess adjacent the inner end of said threaded finish, the improvement comprising: said tamper-evident ring including an upper edge ( 44 ) adjacent points of interconnection with said free edge of said closure, a relatively thin medially disposed portion ( 48 ) depending from said upper edge, and a relatively thicker lower annular main body ( 53 ) bounded by an upper radially extending surface ( 44 ); and a cylindrical inner surface ( 55 ), said surfaces ( 44 )( 55 ) meeting at an angularly disposed area ( 60 ) of relatively thin cross section; a plurality of radially inwardly directed tabs ( 61 ) pivotally secured at said angularly disposed area ( 60 ), said tabs each including a surface ( 70 ) extending radially inwardly of said area, a portion of said surface of said tabs ( 70 ) selectively contacting said cylindrical inner surface ( 55 ) to limit inward movement of said tab during unthreading of said closure. 
     
     
       2. A threaded closure in accordance with claim  1 , in which said surface of said tabs is formed by integrally formed projections at each lateral edge of said tabs. 
     
     
       3. A threaded closure in accordance with claim  1 , in which said surface of said tabs is supplemented by integrally formed projections at each lateral edge of said tabs. 
     
     
       4. A threaded closure in accordance with claim  1  in which pivotal inward movement of said tabs relative to the axis of said closure is limited to between 20 and 49 degrees. 
     
     
       5. In a threaded closure for sealing a container having a corresponding threaded finish, said closure having a tamper-evident ring frangibly interconnected to said closure at a circular free edge thereof, said container defining an annular recess adjacent the inner end of said threaded finish, the improvement comprising: said tamper-evident ring including an upper edge adjacent points of interconnection with said free edge of said closure, a relatively thin medially disposed portion ( 48 ) depending from said upper edge, an annular main body ( 53 ) of relatively thicker cross section bounded by an upper surface ( 54 ) and a cylindrical inner surface ( 55 ), said surfaces ( 54 ) ( 55 )meeting at an area ( 60 ) of relatively thin cross section; plurality of radially inwardly directed tabs ( 61 ) each pivotally secured at said area ( 60 ) of thin cross section, said tabs ( 61 ) each including a surface ( 68 ) extending radially inwardly of said area of thin cross section, a portion of said surface of said tabs ( 68 ) selectively contacting said cylindrical inner surface ( 55 ) to limit inward movement of said tabs during unthreading of said closure. 
     
     
       6. In a threaded closure for sealing a container having a corresponding threaded finish, said closure having a tamper-evident ring frangibly interconnected to said closure at a circular free edge thereof, said container defining an annular recess adjacent the inner end of said threaded finish, the improvement comprising: said tamper-evident ring including an upper edge adjacent points of interconnection with said free edge of said closure, a relatively thin medially disposed portion ( 48 ) depending from said upper edge, a radially extending surface ( 44 ), and a generally cylindrical inner surface ( 55 ), said surfaces meeting at an area ( 60 ) of relatively thin cross section; a plurality of radially inwardly directed tabs ( 61 ) pivotally secured at said area ( 60 ) of thin cross section said tabs each including a plurality of surfaces ( 70 ) extending radially inward of said area ( 60 ) of thin cross section, a portion of one of said surfaces of said tabs selectively contacting said cylindrical inner surface ( 55 ) to limit inward movement of said tabs during unthreading of said closure.